59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

Been awhile since I posted on this site (I'm more active on the HAMB, but you guys are the flathead gurus...and thank you for that!).

The combo is a 59AB + .080, 500 miles on rebuild, Eddie Meyer heads and intake, 2 - 94's, Isky Max-1, HC dual point/dual coil, 78-8501-n, & 78-8502-n waterpumps, 180 degree thermostats, custom built brass rad, with 7lb rad cap, and coolant recovery tank.

Engine runs cool, 170-175 degrees on the gauge in traffic or the highway.

Last weekend we were on a 5 hour highway trek to a car show, travelling at around 60 mph (29" tall tires, 3.78 gears, revving between 2600-2700rpm...a speed where the flatty seemed pretty happy and was pulling in some nice fuel economy). The road included climbing sustained mountain passes where the temp would go to 180-185 (still pretty cool). But then one of the guys that was following me told me I was losing fluid. Stopping to check, I discovered that I was losing coolant out the overflow of the coolant recovery tank. Engine temp was still good, hand on the rad confirmed it was not overheating. I made it to the destination, but upon checking the coolant level there found that I had lost a gallon of coolant, and the green drops of coolant on my black chassis where the overflow of the coolant recovery tank dumps indicates that it continued to drip for the balance of the trip.

After topping up the system with water (had been a 50/50 mix of water and Prestone antifreeze), with the rad cap off and the engine running, I saw the coolant foaming. Fearing a head gasket issue (copper, big bore head gaskets), I left the car in the driveway for the weekend, and then rented a trailer so the car had a stretcher ride home.

Yesterday, now in the shop: I did a compression check - 6 holes are 170lbs, #6 hole is 165lbs, and #2 hole is 160lbs. All 8 plugs look identical (none have telltale of water or steam. I did a CO test for the coolant and found that there wasn't any exhaust gas present in the coolant. I was unable to duplicate the coolant dumping from the overflow while running in the shop (in neutral) at higher rpms. I pressure tested the cooling system and it held 6lbs of pressure for 15 minutes. The coolant was not foaming.

I've not yet checked the rad cap (will do that when I get back down to the shop).

I was thinking that if I replace the head gaskets, I would go with Felpro composite rather than the copper, and replace the grade 8 bolts with an ARP stud kit (boy they want a lot of $ for those!), but want to be sure that this will cure the issue before I go through the effort and expense. There is also the possibility that the water pumps are overpowering the rad flow at that RPM, but I would have thought the 7lb rad cap and the coolant recovery system would have dealt with that.

What do you experts think and advise? Please and thank you in advance.

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Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

It sounds like you've eliminated a head gasket leak, so I'm puzzled as to why you'd consider changing gaskets and studs. Other possible causes also seem to have been eliminated, except the coolant itself. Foaming coolant is expansive, overflowing system capacities. I'd resolve that issue before anything else anyway.

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

I wondered if the foaming/frothing coolant was a result of operating with a lot of air in the system (a gallon low). Yesterday while running in the shop did not see any foaming. Thought it was aresult of the issue and not the cause.

Just finished testing the rad cap...held to 7.5lbs, then released...works and sealed as it should.

Thought maybe the head gasket was starting to fail under load? FRankly, I'm guessing, and seeking all of your wise advice and input.

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

I wouldn't start taking anything apart unless you are sure there is an issue. In my opinion you are running the engine to cool, especially with a pressure cap. I would want it up in the 190 -195 range. If you run into the foam issue again I would try stright water and see if the antifreeze is the problem.

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

I may be wrong but, back when these engines were produced the speed limit was quit a bit lower than what we consider normal today. I'm guessing 55 MPH was about the norm considering the roads. Could it be that today's highway speeds have something to do with coolant overflow?

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

You lived in a different place than I did! The speed limits on the highway or any open roads was unlimited, as in didn't exist. The only limits were in populated high density areas. Everyone I knew drove them full out. I'm not sure where all these theories about put-putting around come from.

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

He says "Engine runs cool, 170-175 degrees in traffic or the highway."

This, with 180 degree stats he says are installed???

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

I saw that and responded I would want it to run at a higher temperature. Most likely a thermostat problem if it is not holding at least 180, but I would switch to a higher temperature thermostat.

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

I might chalk the 170 degrees to variance in the Stewart Warner electric temp gauges. On start up, the engine quickly rises to 170-175 on the gauge and then is rock solid. There may be room to run a warmer thermostat, but I'm not sure how this might affect the issue at hand (mysteriously losing fluid out the overflow tube at hwy speed).

And again, thank you for the responses and for thinking about the problem. I appreciate the discussion.

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

I am by no means an expert but I had a problem with my 59 throwing out the overflow and the problem was the cap lost its seal. New cap, end of my problem.

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

Are you putting in too much coolant? I don't think the recovery tank should be too full. Try just putting enough coolant in the system to maintain a small amount in the recovery tank and see if it still overflows.

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

I started with the top inch or so of the top rad tank and the recovery tank being empty. On top of that, it lost another gallon. I'm not sure if it would keep puking (I chickened out, and didn't want to hurt the motor).

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

I have a similar problem with my 39. I traveled to Back to the Fifties this past weekend, about a 300 mile trip one way. After arriving I had to add about 2 quarts of water. Mine is an open system with no pressure cap. Coming back, same story. My radiator is original and I was thinking that it probably can't candle the flow anymore. I was generally running around 23-2500 rpm. By the way, I averaged 18mpg. Also I run water with no anti-freeze.

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

A "friend" I know hooked the tube from the radiator neck to the wrong tube on the coolant recovery tank. So the hot fluid went in the tall tube and blew right out the bottom.

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

Too much coolant and maybe the 7lb rad cap. It'd didn't over heat, so tell the guy you used your batman slick feature to evade him.

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

I have a 36 and a 38 mostly stock. It's beyond my time but I believe most gas stations had water spickets to top off. Or you carried it on a running board.


20 yrs earlier you had a driver / mechanic that maintained it while you did stuff. :)

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

I built the coolant overflow tank...so you never know, maybe I built it backwards, lol. I'll be looking into that when I get back into the shop tomorrow. Thanks for the idea.

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

I understand that too much coolant to begin with might have been an issue...but I would have thought the 7 lb rad cap would have helped (and the recapture of coolant in the recovery tank...assuming as mentioned above it was built and connected correctly). If I'm wrong I would love to know how/why, could you explain? Thanks.

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

Be certain the cap is actually sealing in the throat of the filler neck. Maybe apply pressure at the connection to the overflow tank to determine viability?

Re: 59AB Cooling System Advice Needed from the Experts (not an overheating issue)
 

I have a coolant system pressure tester which includes a simulated filler neck to pressure test the rad cap. I tested it yesterday it held to 7 lbs, released at 7.5 lbs. I checked the lower sealing surface on the radiator filler neck. It is nice and flat, and was.050" shallower than the testers neck (so should seal with a slightly higher pressure on the rubber seal). Thanks for your reply.